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TT: Fachverband Tiefe Temperaturen
TT 10: Topology: Majorana Physics I
TT 10.6: Talk
Monday, March 18, 2024, 16:15–16:30, H 2053
How symmetry and topology bring order into the mess of vortex core states — •Thomas Gozlinski1,2, Qili Li1, Rolf Heid1, Ryohei Nemoto3, Roland Willa1, Toyo Kazu Yamada3, Jörg Schmalian1, and Wulf Wulfhekel1 — 1Karlsruhe Institute of Technology (KIT) — 2Ludwig-Maximilians-Universität München (LMU) — 3Chiba University, Japan
One popular approach of engineering Majorana bound states has been the combination of an s-wave superconductor and a topological insulator which is proposed to support Majorana zero modes in its vortex cores [1]. In principle, this state should be detectable as a zero bias conductance peak (ZBCP) in a scanning tunneling experiment. However, not every ZBCP is due to a Majorana bound state. In vortex cores, Caroli-de Gennes-Matricon (CdGM) states [2] are ubiquitous and can be mistaken for Majorana bound states. We use high-resolution scanning tunneling spectroscopy and semi-classical Eilenberger simulations to break down the complexity of the local density of states (LDOS) patterns these CdGM states can form [3]. We start from the simplest case of a single-flux-quantum vortex in an s-wave superconductor and successively increase the complexity through Fermi surface anisotropy, multi-band superconductivity and higher flux quantum numbers to understand the LDOS patterns observed in our experiment.
[1] L. Fu, C.L. Kane, Phys. Rev. Lett. 100 (2008) 096407
[2] C. Caroli, P.G. De Gennes, J. Matricon, Phys. Lett. 9 (1964) 307
[3] T. Gozlinski et al., Sci. Adv. 9 (2023) eadh9163
Keywords: Vortices; Caroli-de Gennes-Matricon states; Topology; Superconductivity; Scanning Tunneling Spectroscopy